Multiple position reclining chair with extendible head-rest



p 1963 F. F. SCHLIEPHACKE 3,102,753

MULTIPLE POSITION RECLINING CHAIR WITH EXTENDIBLE HEAD-REST Filed Aug. 4, 1960 INV EN TOR.

FR/DTJOF F .SCf/L/EPHA CKE mvbzg cle of furniture.

United States Patent 3,102,753 MULTIPLE PUSITION REEILINING CHAIR WITH EXTENDEBLE HEAD-REST Fridtiof F. Schliephacke, Berlin-fichmargendorf, Germany, assignor to Anton Lorenz, Boynton Beach, Fla. Filed Aug. 4, 1960, Ser. No. 47,450 3 Claims. (Cl. 297-61) The present invention relates generally to reclining chairs and in particular to an improved head-rest mounting and actuating arrangement for a reclining chair of the multiple position type.

Reclining chairs of the multiple position type generally include a support and a body-supporting structure ineluding a back-rest and seat which are mounted on the support for movement from a normal sitting position through a first movement phase to an intermediate position. Further movement for the intermediate position through a second movement phase is effective to bring the reclining chair to its full reclining position. In such chairs, styling requirements often call for a relatively low back-rest, in which case it is advantageous to provide a separate head-rest which extends upwardly above the top surface of the back-rest and in position to support the occupants head when the chair is in use. Normally, the head-rest is retracted within the body of the badrest in the sitting position of the chair so as not to detract from the low-back styling of the chair. Means are provided, however, for automatically moving the headrest to its extended, head-supporting position when bodysupporting structure is moved to itsinterrnediate position and for maintaining the head-rest in its extended position when the body-supporting unit is moved to its fully reclined position.

In multiple position chairs of this type, there exists a need for a mounting and actuating arrangement for headrests which is relatively compact, which is inexpensive in manufacture, which is compatible with the mechanisms for achieving movement of the body-supporting structure and which is easily incorporated with an upholstered arti- The last mentioned requirement is of particular significance where the head-rest is to be inoorporated into a reclining chair of modern design wherein relatively slim constructions are deemed desirable. Therefore, a need exists for a mounting arrangement for a head rest which requires no more than the usual depth of the back-rest of a reclining chair body-supporting unit. Further, the mounting of the head-rest onto the backrest should be compatible with the normal requirements of ease of upholstering such that a well tailored reclining chair may be manufactured on a mass production basis at a relatively low unit cost.

It will be appreciated that compactness of design and simplicity of shape in the head-rest and its associated mounting and activating arrangement makes it possible to incorporate the head-rest into the upper rearward corner of the back-rest such that the same is relatively hidden from view when the head rest is in its stored or retracted position. Further, a simple and compact design of the head-rest mounting and actuating arrangement provides for the extension of the head-rest to the head supporting or extended position without the undue exposure of the internal framework of the back-rest or of the head-rest mounting and actuating arrangement.

Broadly, it is an object of the present invention to provide an improved head-rest mounting and actuating arrangement which realizes one or more of the aforesaid objectives. Specifically, it is among the objects of the invention to provide a relatively compact head-rest mounting and actuating arrangement for reclining chair which is readily incorporated within a chair of modern slim 3,102,753 Patented Sept. 3, 1.963

there is provided a head-rest mounting and actuating arrangement for a reclining chair of the multiple position type including a support and body-supporting means having a back-rest and seat mounted on the support for movement from a seating position through a first movement phase to an intermediate position and for movement from the intermediate position through a second movement phase to a reclining position. The head-rest is provided with a single pivotal mount on the b ack-rest for rotation about said pivotal mount from a retracted position within the back-rest to an extended, head-supporting position. Actuating means are provided to effect the rotation of the head-rest and includes a pair of interconnected links, one of which is pivotally mounted on the backrest and the other of which is pivo-tally connected to the headrest. Drive means are also provided to operate the actuating means in response to the first movement phase.

Specifically, the actuating means includes a link connecting the pair of links to the mechanism controlling the body-supporting structure so as to extend the head-rest during the first motion phase and to maintain the headrest extended during the second motion phase.

The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred embodiment when taken in conjunction with the following drawings, wherein;

FIG. 1 is a side elevational view with parts broken away and shown in section, of a typical reclining chair of the multiple position rester type embodying a head-rest mounting and actuating arrangement demonstrating features of the present invention, the chair being shown in an upright or sitting position with the head-rest in its retracted position;

FIG. 2 is a side elevational view similar to FIG. 1, but with the chair shown in its intermediate, tilted sitting position with the head-rest shown in its extended headsupporting position;

FIG. 3 is a side elevational view similar to FIG. 2 showing the chair in a fully reclined position with the head-rest in its extended head-supporting position relative to the back-rest.

Specific reference will now be made to the drawings wherein there is shown a reclining chair of the multiple position r-ester type, generally designated by the reference numeral 10, which includes a support 12 having opposed side frames 14 interconnected by a number of cross braces r16. The side frames 14 are supported by relatively high legs 18 in accordance with modern styling. Mounted on the support is a body-supporting unit 20 in eluding a back-rest 22 and a seat 24 which is movable from an upright or sitting position shown in FIG. 1 through a first movement phase to an intermediate, tilted sitting position shown in FIG. 2; and for further movement from the intermediate, tilted sitting position through a second movement phase to a reclining position shown in FIG. 3. In this type of chair it is usual to provide a leg-rest, not shown, which is mounted for movement from a stored position below the seat to an extended and elevated leg-supporting position forwardly of the seat during the first movement phase such that an adequate leg support is provided for the chair occupant inthe intermediate, tilted sitting position of FIG. 2 and in the recling position of FIG. 3. However, since the leg-rest invention herein.

w and its specific mounting arrangement does not constitute a part of the present invention, it is not shown or described herein.

The chair structure also includes a retractable headrest 26 and an actuating linkage therefor constituting the The back-rest 22 has a recessed portion at its upper end which receives the head-rest 26 in the retracted position thereof, as shown in FIG. 1. head-rest 26 has an integral extension or car 28 which is mounted by a fixed pivot 3i) on the upper end portion of the back-rest 22. The head-rest 26 is thus turnable about its pivotal mount 36 from the retracted position of FIG. 1, in which it is inverted and concealed within the upper rear corner of the back-rest 22 to the extended position of FIGS. 2 and 3 in which it is disposed in upright position above the top surface of the back-rest 22 with its head-supporting surface 26a in position to support the head of the chair occupant and properly oriented with the back-supporting surface 22a of back-rest 22.

Actuating means, generally designated by the reference numeral 32, is provided to rotate the head-rest 26 about its pivotal mount 30. The actuating means 32 includes a first link 34 which is pivotally mounted at one end on the back rest 22 by pivot 36 which is spaced from the pivot 30. A second link '38 is connected to the headrest 26 by pivot 40' at a point spaced from the head-rest extension 28 and the pivotal mount 30. The free, op-

. posite ends of each of the links 34, 38 are pivotally interconnected at 42. The links 34, 38 are so arranged that in the retracted head-rest position of FIG. 1, they extend downwardly and inwardly toward their pivotal interconnection 42, forming an angle whose apex is lower than the pivot points 36, 40. It will be appreciated that when the first link 3'4 is rotated rearwardly and upwardly about its pivotal mount 36, that is to say, in a counterclockwise direction as viewed in FIG. 1, the second link 38 .will turn the head-rest 26 about its pivotal mount 30. The headrest 26 is thus moved first rearwardly out of its stored position within the back-rest 22 and then upwardly and forwardly through an angle of 180 into the extended head-supporting position as shown in FIGS. 2 and 3.

The actuating means 32, the head-rest 26, and the upper portion of the back-rest 22 form a four-bar linkage wherein the portion of the black-rest 22 between the pivots 30 and 36'forms the stationary member of the fourbar linkage. The link 34 forms a first movable link of the four-bar linkage, the link 38, a second movable link, and the portion of the head-rest '26 between pivots 3t and 40' a third movable link.

7 The head-rest 26 moves from its stored or retracted position of FIG. 1 to the extended head-supporting position of 'FIG. 2 relative to the back-rest 22 as the bodysupporting unit 20 moves from its upright sitting position through the first movement phase to the intermediate position as shown in FIG. 2. The relative positions of the head-rest 26 and the back-rest 22 remain substantially constantas the body-supporting unit is further moved through its second movement phase from its intermediate position of FIG. 2 to its fully-reclined position shown in which includes a front pivotal mount '48 confined within a front guiding slot 50 provided in a mounting bnacket or plate 52 fixed to the chair frame or support 12. The

, front pivotal mount provides a relatively fixed pivot for the front guiding link 46 during the first movement phase, as may be appreciated by inspecting FIGS. 1 and 2, and enables a lost motion travel of the front guiding link 46 The . 4. relative to the support during the second movement phase, as may be appreciated by inspecting FIGS. 2 and 3. At its upper end, the front guiding link 46 has a pivotal connection 54- to the seat 24 0f the body-supporting unit 20. Disposed rearwardly of the front guiding link 46 is a rear guiding link 56 which has a rear pivotal mount 58 on the chair frame or support at its lower end and a rear pivotal connection 60 at its upper end to the seat 24 at a point spaced rearwardly of the front pivotal connection 54. The front and rear guiding links 46, 56 will be recognized as providing a four-bar guiding linkage for the body-supporting unit 20, which four-bar guiding linkage includes a stationary link intermediate the front the rear pivotal mounts 48, 58, the front guiding link 46 as a first movable link, the portion of the seat intermediate the front and rear pivotal connections 54, 66 as a second movable link, and the rear guiding link 56 as a third movable link. During the first movement phase the fourbar guiding linkage guides the body-supporting unit rearwardly while imparting an appropriate tilt or inclination thereto; and during the second movement phase the rear pivotal connection 60 to the body-supporting unit 2i) serves as a relatively fixed main pivot about which the body-supporting unit 20 turns, with the front guiding link translating relative to the support incident to the travel of the front pivotal mount 48 upwardly along the front guiding slot '50.

In order to block the four-bar guiding linkage at the 'end of the first movement phase, a stop is provided to engage one of the links thereof in the intermediate, tilted sitting position shown in IFIG. 2. In this illustrative embodiment, one of the cross braces 16 located rearwardly of the rear guiding link 56 carries a stop 6-2 which abuts the rear guiding link 56 in the intermediate, tilted sitting position of the body-supporting unit 29 to block the continued rearward turning movement of the rear guiding link such that the rear pivotal connections 60 serve as the fixed main pivot during the second movement phase.

A sequencing means is operatively connected to the front guiding link 46 for precluding lost motion travel thereof relative to the support during the first movement phase. The [front guiding link 46 includes a rigid extension 64 which carries a sequencing pin 66 confined within a double-arc slot 68. The double-arc slot 68 in cludes a first section 68a having an are on a radius about the front pivot mount 48 and a second section 68b having curvature corresponding substantially to that of the lost motion slot 50 and parallel thereto. During the first movement phase, sequencing pin 66 moves from x the rearward end of the slot section 68a to the junction of the slot sections 68a, 68b and confines the front pivotal mount 48 to the lower end of the slot 50'. However, during the second movement phase and upon blocking of the four-bar guiding linkage the sequencing means permits the lost motion travel of the respective pins 48, 66 along the slots 50, 68b.

A head-rest drive arrangement is operatively connected to the actuating mechanism 32 for the head-rest 26 and to the four-bar guiding linkage for the body-supporting unit 20 to move the head-rest 26 to the extended head-supporting position during the first movement phase, with the head-rest remaining in a relatively stationary position in the back-rest 22 during the second movement phase. The drive arrangement includes a double-arm lever 70 which is pivotally mounted intermediate its ends at a pivotal mount 72 on a bracket 74 fixed to the body-supporting unit 20. The downwardly and rearwardly directed arm 70a of the double-arm lever is coupled via a connecting link 76 to the first link 34- of the actuating mechanism 32, intermediate the ends of said link 34. The connecting link 76 has a pivotal connection 78 at its lower end to the arm 70a of the doublearm= lever 70 and a pivotal connection 80 to an intermediate point on the link 34. The upwardly directed arm 70:) of the lever 70 is coupled via a constraining link 82 to the front guiding link 46. Specifically, the rearward end of the constraining link 82 has a pivotal connection 84 to the arm 70b and a further pivotal connection to the lower end of the front guiding link 46 at the front pivotal mount 48.

The link 82, which serves as a constraining means, is effective to bring about the extension of the head-rest 26 incident to the relative movement between the body-supporting unit 20 and the front pivotal mount, 48 during the first movement phase such that the bead-rest moves to the extended headeupporting position. Specifically, as the body-supporting unit 20 moves rearwardly during the first movement phase, with thefront pivotal mount 48 remaining at the lower end of the lost motion slot '50, the constraining link 82 causes the lever 70 to turn such that the arm 70a thereof is driven through an upward arc in the counterclockwise direction about the pivot mount 72 on the body-supporting unit 20. This imparts an upward thrust to the connecting link '76 which turns the first link 34 in a counterclockwise direction about its pivotal mount 36 on the back-rest 22 to bring about the rotation of the head-rest 26. The curvature of the lost motion slot 50 for the front guiding link 46 is on a radius about the pivotal connection 84 ofthe constraining link 82 to the actuating lever 70 such that during the second movement phase, the displacement of the front pivot mount 48 along the lost motion slot 50 causes the constraining link 82 to merely turn about the pivotal connection 84 and impart no further movement to the head-rest. For all intents and purposes the head-rest when extended in the response to movement of the bodysup-porting unit 20 into the intermediate, tilted sitting position, remains in the extended head-supporting position through the second movement phase and as the chair moves through the various reclining positions to the fully reclining position illustrated in FIG. 3.

In order to facilitate a more thorough understanding of the present invention, a typical sequence of operations ,will now be described.

When the chair occupant is seated in the body-supporting unit 29 and urges his or her weight rearwardly, the body-supporting unit 20 translates rearwardly relative to the support 12 under the guiding action of the four bar guiding linkage provided by the front and rear guiding links 46, 56 and their respective pivotal mounts and pivotal connections. Incident to such rearward movement, and with the front pivotal mount 48 remaining at the lower end of the lost motion slot 50, a constraint is exercised by the constraining link 82 on the arm 70b of the lever 70 which lever translates rearwardly due to its pivotal mounts 72 on the body-supporting unit. This constraint is effective to turn the arm 70a of the double-arm lever 70 through an upward and rearward are which is effective to impart a thrust via the connecting link 76 to the actuating mechanism 32 for the head-rest 26. During the first portion of this thrust the first link 34- is driven in a counterclockwise direction about the second pivot point 36 on the back-rest 22'. This rotation of the first link .34 is effective to move the pivotal connection 40 of the second drive link 38 and the head-rest 26 through a counter-clockwise rotational motion about the first pivotal mount 30. The initial rotation of the head-rest 26 is effective to move the body of the head-rest -26 rearwardly from the back-rest 22 such that it is removed from its containment therein. After the head-rest 26 has achieved a substantially horizontal orientation, further upward movement of the connecting link 7 6', as moved by the lever 70, is effective to further rotate the first drive link 34 and thereby to further rotate the head-rest 26 to its extended headsupporting position above the back-rest 22 and substantially parallel thereto. The head-rest 26 arrives in the appropriate head-supporting position when the rear guiding link 56 abuts the stop 22. Thereafter, and through- 6 out the second movement phase, the constraint is effectively removed from the double-arm lever 70 due to the lost motion travel of the front pivotal mount 48 along the front guiding slot 50 and the head-rest 26 remains in the extended head-supporting position with substantially no relative movement in relation to the backrest 22. During such second movement phase, the body-supporting unit turns about the rear pivotal connection 60 as a main pivot, with the front pivotal mount 48 moving through an appropriate lost motion travel.

In the extended head-rest position of FIGS. 2 and 3, the links 34 and 38 extend rearwardly toward their pivotal interconnection 42. The angle between these links 34- and 38 has increased from that formed in the sitting position of FIG. 1, and the pivot 40 is spaced above the pivot 36 with the pivot 42 being located rearward'ly and, substantially centrally of a line between the pivots 36 and 40. Stated differently, the links 34 and 38 form a toggle linkage which, in the extended position, define a forwardly-directed angle wthose apex is located rearwardly of the pivots 36 and 40.

In this extended position, the head-rest 26 rests upon a fixed portion of the back-rest frame structure, the latter preventing wobble or forward displacement of the head-rest from its extended position due to loose or sloppy pivot bearings.

When the chair occupant desires to restore the chair to the upright or sitting position, it is merely necessary to urge his or her weight forwardly and press against the leg-rest (not shown), and the chair will move through the reverse sequence of operations, with the head-rest remaining relatively stationary throughout the second movement phase and until such time as the intermediate tilted sitting position is established. However, in response to the reverse movement through the first movement phase, the head-rest will swing rearwardly relative to the back-rest and be restored to the stored position illustrated in FIG. 1.

From the foregoing it will be appreciated that there has been provided, in accordance with the present invention, a compact head-rest mounting and actuating arrangement for a reclining chair of the multiple position type, which will be readily incorporated into a chair of modern styling. Such head-rest mounting linkage is of a construction to be readily incorporated into the limited physical space available for the arrangement, and may be readily actuated from the main actuating or coordinating mechanisms of the chair. A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding .use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

What I claim is:

1. A head-rest and mouunting and actuating arrangement for a reclining chair of the multiple position type including a support, a body-supporting structure comprising a back-rest and seat, and means mounting said body-supporting structure on said support for movement from a sitting position through a first movement phase to an intermediate position and for movement from said intermediate position through a second movement phase to a reclining position; said arrangement comprising a head-rest pivotally mounted on said back-rest. at a first pivotal mount for rotation through substantially from a retracted position to an extended head-supporting position, first and second links pivotally connected to each other, said first link being pivotally mounted at one end on said back-rest at a second pivotal mount spaced from said first pivotal mount, said second link being pivotally connected at one end to said head-rest at a pivotal connection spaced from said first pivotal mount, said first link, said second link and said head-rest intermediate said first pivotal mount and said pivotal connection serving as three movable links of a four-bar linkage including said back-rest intermediate said first pivotal mount and said second pivotal mount as the stationary link thereof, and drive means operatively connecting one of said first and second links to said body-supporting structure mounting means for actuating said tour-bar mounting linkage and for pivoting said head-rest about said first pivotal mount through substantially 180 during said first phase for maintaining said head-rest in said extended,

head-supporting position.

2. A head-rest and mounting and actuating arrangement for a reclining chair of the multiple position type including a support, a body-supporting structure comprising a back-rest and seat, and means mounting said body-supporting structure on said support for movement from a sitting position through a first movement phase to an intermediate position and for movement from said intermediate position through a secondmovernent phase to a reclining position; said arrangement comprising a head-rest pivotally mounted on said back-rest at a first pivotal mount for rotation through substantially 180 from a retracted position to an extended head-supporting position, first and second links pivotally connected to each other, said first link being pivotally mounted at one end on said back-rest at a second pivotal mount spaced from said first pivotal mount, said second link being pivotally connected at one end to said head-rest at a pivotal connection spaced from said first pivotal mount, said first link, said second link and said head-rest intermediate said first pivotal mount and said pivotal connection serving as three movable links of a four-bar linkage including said back-rest intermediate said first pivotal mount and said second pivotal mount as the stationary link thereof, said first and second link forming a toggle linkage with said links opening upwardly with a small angle therehetween when said head-rest is in its retracted position and opening forwardly of said chair with a relatively large angle therebetween when the head-rest is in the extended head-supporting position, and drive means operatively connecting one of said first and second links to said body-supporting structure mounting means for actuating said four-bar mounting linkage, for opening the angle of said toggle linkage, and for pivoting said headrest about said first pivotal mount through substantially 180 during said first movement phase, said drive means being stationary with respect to said back-rest during said second movement phase for maintaining said head-rest in said extended, head-supporting position.

3. A head-rest and mounting and actuating arrangement for a reclining chair of the multiple position type including a support, a body-supporting structure comprising a back-rest and seat, and means mounting said body-supporting structure on said support tormovement from a sitting position through a first movement phase to an intermediate position and rfor movement from said intermediate position through asecond movement phase to a reclining position; said arrangement comprising a head-rest pivotally mounted on said back-rest at 'a first pivotal mount for rotation through substantially from a retracted position to an extended head-supporting position, first and second links pivotallyconnect'ed to each other, said first link being pivotally mounted at one end onsaid back-rest at a second pivotal mount spaced from said first pivotal mount, said second link being pivotally connected at one end to said head-rest at a pivotal con nection spaced from said first pivotal mount, said first link, said second link and said head-rest intermediate said first pivotal mount and said pivotal connection serving as three movable links of a four-bar linkage including said hack-rest intermediate said first pivotal mount and said second pivotal mount as the stationary link thereof, said first and second link forming a toggle linkage with said links opening upwardly with a small angle therebetween when said head-rest is in its retracted position and opening forwardly of said chair with a relatively large angle therebetween when the head-rest is in the extended head-supporting position, and drive means operatively connecting one of said first and second links to said body-supporting structure mounting means for actuatingsaid four-bar mounting linkage, for opening the angle of said toggle linkage and for pivoting said head-rest about said first pivotal mount through substantially 180 during said first movement phase including a double-arm lever pivotally mounted on said body-supporting unit intermediate. its ends, and a driving link pivotally connected between one end of said lever andisaid toggle linkage, the other end of said lever being operatively connected to said bodysupporting structure mounting means for driving said toggle linkage during the first movement phase to open the angle between said first andsecond link to swing said headrest through substantially 180 with respect to said 45 back-rest during the first movement phase, and to hold said head-rest stationary with respect to said back-rest during the second movement phase.

References Cited in the file of this patent UNITED STATES PATENTS Spound Aug. 2, 1960 

1. A HEAD-REST AND MOUNTING AND ACTUATING ARRANGEMENT FOR A RECLINING CHAIR OF THE MULTIPLE POSITION TYPE INCLUDING A SUPPORT, A BODY-SUPPORTING STRUCTURE COMPRISING A BACK-REST AND SEAT, AND MEANS MOUNTING SAID BODY-SUPPORTING STRUCTURE ON SAID SUPPORT FOR MOVEMENT FROM A SITTING POSITION THROUGH A FIRST MOVEMENT PHASE TO AN INTERMEDIATE POSITION AND FOR MOVEMENT FROM SAID INTERMEDIATE POSITION THROUGH A SECOND MOVEMENT PHASE TO A RECLINING POSITION; SAID ARRANGEMENT COMPRISING A HEAD-REST PIVOTALLY MOUNTED ON SAID BACK-REST AT A FIRST PIVOTAL MOUNT FOR ROTATION THROUGH SUBSTANTIALLY 180* FROM A RETRACTED POSITION TO AN EXTENDED HEAD-SUPPORTING POSITION, FIRST AND SECOND LINKS PIVOTALLY CONNECTED TO EACH OTHER, SAID FIRST LINK BEING PIVOTALLY MOUNTED AT ONE END ON SAID BACK-REST AT A SECOND PIVOTAL MOUNT SPACED FROM SAID FIRST PIVOTAL MOUNT, SAID SECOND LINK BEING PIVOTALLY CONNECTED AT ONE END TO SAID HEAD-REST AT A PIVOTAL CONNECTION SPACED FROM SAID FIRST PIVOTAL MOUNT, SAID FIRST LINK, SAID SECOND LINK AND SAID HEAD-REST INTERMEDIATE SAID FIRST PIVOTAL MOUNT AND SAID PIVOTAL CONNECTION SERVING AS THREE MOVABLE LINKS OF A FOUR-BAR LINKAGE INCLUDING SAID BACK-REST INTERMEDIATE SAID FIRST PIVOTAL MOUNT AND SAID SECOND PIVOTAL MOUNT AS THE STATIONARY LINK THEREOF, AND DRIVE MEANS OPERATIVELY CONNECTING ONE OF SAID FIRST AND SECOND LINKS TO SAID BODY-SUPPORTING STRUCTURE MOUNTING MEANS FOR ACTUATING SAID FOUR-BAR MOUNTING LINKAGE AND FOR PIVOTING SAID HEAD-REST ABOUT SAID FIRST PIVOTAL MOUNT THROUGH SUBSTANTIALLY 180* DURING SAID FIRST MOVEMENT PHASE INCLUDING A DOUBLE-ARM LEVER PIVOTALLY MOUNTED INTERMEDIATE ITS ENDS ON SAID BODY-SUPPORTING STRUCTURE, AND A DRIVING LINK CONNECTING ONE END OF SAID LEVER TO SAID ONE OF SAID FIRST AND SECOND LINKS, THE OTHER ARM OF SAID LEVER BEING OPERATIVELY CONNECTED TO SAID BODY-SUPPORTING STRUCTURE MOUNTING MEANS FOR DRIVING SAID FOUR-BAR LINKAGE DURING THE FIRST MOVEMENT PHASE AND FOR HOLDING SAID FOUR-BAR LINKAGE STATIONARY WITH RESPECT TO SAID BACK-REST DURING SAID SECOND MOVEMENT PHASE FOR MAINTAINING SAID HEAD-REST IN SAID EXTENDED, HEAD-SUPPORTING POSITION. 